1. Field of the Invention
The present invention relates to an image display apparatus for projecting an image of an image bearing member such as a film onto a screen, and reading thus displayed image with an image sensor for obtaining image signals.
2. Related Background Art
In the conventional image display/reading apparatus, a switching mirror has been employed for selecting either a display optical path for projecting the film image onto a display screen, or a reading optical path for projecting said image onto a sensor array (image sensor). More specifically, as shown in FIG. 7, the image of the microfilm F illuminated by a lamp 1 is projected by a projection lens 2 and is reflected by a scan mirror 3, and there is provided a display optical path for image projection onto a screen 6 through a switchable mirror 4 in the solid-lined position and a fixed mirror 5, and a reading optical path leading to a sensor array 9 through fixed mirrors 7, 8, with the switching mirror 4 in the broken-lined position outside the optical path.
In such conventional structure, however, the display optical path and the reading optical path are completely separate after the switching mirror 4, thus requiring a large space and an elevated cost due to the presence of mirrors as explained above. In addition there is required delicate adjustment of mirrors for matching the center of the display optical path with that of the reading optical path, so that the image on the screen 6 becomes often displaced from the image on the sensor array.